/GH
This option calls the __pexit function at the end of every method or function. The __pexit function is not part of any library and it is up to you to provide a definition for __pexit. Use assembly language to write the function.
Unless you plan to explicitly call __pexit, you do not need to provide a prototype. The function must appear as if it had the following prototype, and it must push the content of all registers on entry and pop the unchanged content on exit:
void __declspec(naked) _cdecl _pexit( void );
__pexit is similar to __penter; see /Gh for an example of how to write a __pexit function.
Compiler Options | Setting Compiler Options